Air-cushion vehicle edge skirt arrangement

Claim 2

In combination with an air-cushion vehicle having a a lift chamber, means for providing pressurized air in said lift chamber, and a generally rigid structure having a lateral surface extending along an edge of said lift chamber, a skirt arrangement for said lift chamber comprising a flexible diaphragm disposed longitudinally of said edge so as to present one side of said diaphragm adjacent said lift chamber, one longitudinal edge of said diaphragm being attached to said vehicle adjacent said edge of said lift chamber, a plate means, said plate means including an edge connected to the lower edge of said diaphragm, a first portion inclined downwardly and inwardly from said edge thereof, and a second generally horizontal portion connected to said first portion at an obtuse angle relative thereto, for being reacted upon by pressures above and below said second portion for moving said skirt arrangement upwardly and downwardly, said second portion being beneath said lateral surface, means for applying pressurized air to the upper surface of said plate means and to said side of said flexible diaphragm, and means interconnecting said plate means and said vehicle, said means interconnecting said plate means and said vehicle including a duality of flexible members, a first end of each of said flexible members being connected to said lateral surface, said first ends being at spaced locations, the opposite second end of each of said flexible members being connected to said plate means, said second ends being at spaced locations, said flexible members together with the portions of said lateral surface and said plate means therebetween defining approximately a parallelogram, for thereby allowing said plate means to move outwardly and upwardly in a stable manner relative to said lateral surface.

Claim 3

A device as recited in claim 1 in which said connections of said first ends of said flexible members are such that said first end of one of said flexible members is laterally outwardly relative to said lift chamber with respect to said first end of the other of said flexible members, said second end of said one flexible member being connected to said first inclined portion of said plate means, said second end of said other flexible member being connected to said second generally horizontal portion of said plate means.

Claim 4

A device as recited in claim 1 in which said flexible members are of an adequate length and connected to said lateral surface at positions such that said plate means can move upwardly to the level of said lateral surface and simultaneously move outwardly a distance sufficient to clear said edge of said lift chamber.

Claim 5

In combination with an air-cushion vehicle having a lift chamber, means for providing pressurized air in said lift chamber, and a generally rigid structure having a lateral surface extending along an edge of said lift chamber, a skirt arrangement for said lift chamber comprising a flexible diaphragm disposed longitudinally of said edge so as to present one side of said diaphragm adjacent said lift chamber, one longitudinal edge of said diaphragm being attached to said vehicle adjacent said edge of said lift chamber, a plate means, said plate means including an edge connected to the lower edge of said dipahragm, said plate means being inclined downwardly from said edge thereof to a portion thereof which is beneath said lateral surface, means for applying pressurized air to the upper surface of said plate means and to said side of said flexible diaphragm, means interconnecting said plate means and said vehicle, and means for moving said skirt arrangement downwardly relative to said lateral surface, said means for moving said skirt arrangement downwardly including movable means carried by said rigid structure at said edge of said lift chamber, said one lOngitudinal edge of said diaphragm being secured to said movable means, whereby movement of said movable means moves said diaphragm therewith, said movable means including a generally horizontal member having an inner edge and an outer edge, and means pivotally attaching said inner edge to said rigid structure so as to position said generally horizontal member adjacent said lateral surface with said outer edge adjacent said edge of said lift chamber, said one longitudinal edge of said diaphragm being attached to said outer edge of said generally horizontal member, said generally horizontal member having an opening means therethrough providing communication between said lift chamber and the space between said generally horizontal member and said lateral surface of said rigid structure.

Claim 6

In combination with an air-cushion vehicle having a lift chamber, means for providing pressurized air in said lift chamber, and a generally rigid structure having a lateral surface extending along an edge of said lift chamber, a skirt arrangement for said lift chamber comprising a flexible diaphragm disposed longitudinally of said edge so as to present one side of said diaphragm adjacent said lift chamber, one longitudinal edge of said diaphragm being attached to said vehicle adjacent said edge of said lift chamber, a plate means, said plate means including an edge connected to the lower edge of said dipahragm, said plate means being inclined downwardly from said edge thereof to a portion thereof which is beneath said lateral surface, means for applying pressurized air to the upper surface of said plate means and to said side of said flexible diaphragm, means interconnecting said plate means and said vehicle, and means for moving said skirt arrangement downwardly relative to said lateral surface, said means for moving said skirt arrangement downwardly including movable means carried by said rigid structure at said edge of said lift chamber, said one lOngitudinal edge of said diaphragm being secured to said movable means, whereby movement of said movable means moves said diaphragm therewith, said movable means including a generally horizontal member having an inner edge and an outer edge, and means pivotally attaching said inner edge to said rigid structure so as to position said generally horizontal member adjacent said lateral surface with said outer edge adjacent said edge of said lift chamber, said one longitudinal edge of said diaphragm being attached to said outer edge of said generally horizontal member, said generally horizontal member having an opening means therethrough providing communication between said lift chamber and the space between said generally horizontal member and said lateral surface of said rigid structure.

Claim 7

A device as recited in claim 4 including means for discharging air from said space laterally with respect to said vehicle upon predetermined downward movement of said generally horizontal member, for thereby imposing a side thrust on said vehicle.

Claim 8

A device as recited in claim 5 in which for said means for discharging air from said space laterally said generally horizontal member includes an upstanding flange on said outer edge thereof, said upstanding flange being normally in sealing relationship with said edge of said lift chamber, said upstanding flange being moved to a position where it is spaced downwardly from said edge of said lift chamber upon said predetermined downward movement of said generally horizontal member.

Claim 9

A device as recited in claim 4 including in addition a second diaphragm interconnecting said outer edge of said generally horizontal member and said edge of said lift chamber for substantially preventing lateral discharge of air from said space upon downward movement of said generally horizontal member.

Claim 10

A device as recited in claim 7 in which said opening means provides restricted communication between said lift chamber and said space, whereby air is substantially retained in said space and provides a springlike action and a damping effect upon oscillation of said generally horizontal member.

Claim 11

In combination with an air-cushion vehicle having a lift chamber having an open bottom, means for providing pressurized air in said lift chamber, and a generally rigid structure having a lateral surface spaced outwardly from the center of said lift chamber and extending along an edge of said lift chamber, a skirt arrangment for said lift chamber comprising a flexible diaphragm disposed longitudinally of said edge so as to present one side of said diaphragm adjacent said lift chamber, one longitudinal edge of said diaphragm being attached to said vehicle adjacent said edge of said lift chamber, a plate means, said plate means including an outer edge connected to the lower edge of said diaphragm, said plate means being inclined downwardly from said outer edge thereof to a portion thereof which is beneath said lateral surface, said plate means including an inner edge spaced outwardly from the center of said lift chamber and adjacent said lateral surface for permitting air to flow from said lift chamber generally horizontally outwardly under said plate means to the exterior of said lift chamber, said plate means including a first downwardly and inwardly inclined portion, and a second generally flat horizontal portion connected to the lower edge of said first portion at an obtuse angle relative thereto and extending inwardly therefrom to said inner edge of said plate, for being reacted upon by pressures above and below said second portion for moving said skirt arrangement upwardly and downwardly, means for applying pressurized air to the upper surface of said plate means and to said side of said flexible diaphragm, and flexible means interconnecting said plate means and said vehicle, said plate means being a flexible sheet member, said means interconnecting sAid plate means and said vehicle including flexible elements attached to said first portion and to said second portion of said plate means for generally maintaining the shape of said plate means when said plate means is so subjected to pressure from pressurized air in said lift chamber.

Claim 12

In combination with an air-cushion vehicle having a lift chamber having an open bottom, means for providing pressurized air in said lift chamber, and a generally rigid structure having a lateral surface spaced outwardly from the center of said lift chamber and extending along an edge of said lift chamber, a skirt arrangment for said lift chamber comprising a flexible diaphragm disposed longitudinally of said edge so as to present one side of said diaphragm adjacent said lift chamber, one longitudinal edge of said diaphragm being attached to said vehicle adjacent said edge of said lift chamber, a plate means, said plate means including an outer edge connected to the lower edge of said diaphragm, said plate means being inclined downwardly from said outer edge thereof to a portion thereof which is beneath said lateral surface, said plate means including an inner edge spaced outwardly from the center of said lift chamber and adjacent said lateral surface for permitting air to flow from said lift chamber generally horizontally outwardly under said plate means to the exterior of said lift chamber, said plate means including a first downwardly and inwardly inclined portion, and a second generally flat horizontal portion connected to the lower edge of said first portion at an obtuse angle relative thereto and extending inwardly therefrom to said inner edge of said plate, for being reacted upon by pressures above and below said second portion for moving said skirt arrangement upwardly and downwardly, means for applying pressurized air to the upper surface of said plate means and to said side of said flexible diaphragm, and flexible means interconnecting said plate means and said vehicle, said plate means being a flexible sheet member, said means interconnecting sAid plate means and said vehicle including flexible elements attached to said first portion and to said second portion of said plate means for generally maintaining the shape of said plate means when said plate means is so subjected to pressure from pressurized air in said lift chamber.

Claim 13

In combination with an air-cushion vehicle having a lift chamber having an open bottom, means for providing pressurized air in said lift chamber, and a generally rigid structure having a lateral surface spaced outwardly from the center of said lift chamber and extending along an edge of said lift chamber at the rearward end thereof, a skirt arrangement for said lift chamber comprising a flexible diaphragm disposed longitudinally of said edge so as to present one side of said diaphragm adjacent said lift chamber, one longitudinal edge of said diaphragm being attached to said vehicle adjacent said edge of said lift chamber, a plate means, said plate means including an outer edge connected to the lower edge of said diaphragm, said plate means being included downwardly from said outer edge thereof to a portion thereof which is beneath said lateral surface, said plate means including an inner edge spaced outwardly from the center of said lift chamber and adjacent said lateral surface for permitting air to flow from said lift chamber generally horizontally outwardly under said plate means to the exterior of said lift chamber, said plate means being a substantially rigid member curved to form a shallow channel with a convex surface facing downwardly, said diaphragm being inclined downwardly and forwardly relative to said vehicle from said attachment thereof adjacent said edge of said lift chamber to said connection thereof to said plate means, means for applying pressurized air to the upper surface of said plate means and to said side of said flexible diaphragm, and flexible means interconnecting said plate means and said vehicle.

Claim 14

In combination with an air-cushion vehicle having a lift chamber having an open bottom, means for providing pressurized air in said lift chamber, and a generally rigid structure having a lateral surface spaced outwardly from the center of said lift chamber and extending along an edge of said lift chamber at the rearward end thereof, a skirt arrangement for said lift chamber comprising a flexible diaphragm disposed longitudinally of said edge so as to present one side of said diaphragm adjacent said lift chamber, one longitudinal edge of said diaphragm being attached to said vehicle adjacent said edge of said lift chamber, a plate means, said plate means including an outer edge connected to the lower edge of said diaphragm, said plate means being included downwardly from said outer edge thereof to a portion thereof which is beneath said lateral surface, said plate means including an inner edge spaced outwardly from the center of said lift chamber and adjacent said lateral surface for permitting air to flow from said lift chamber generally horizontally outwardly under said plate means to the exterior of said lift chamber, said plate means being a substantially rigid member curved to form a shallow channel with a convex surface facing downwardly, said diaphragm being inclined downwardly and forwardly relative to said vehicle from said attachment thereof adjacent said edge of said lift chamber to said connection thereof to said plate means, means for applying pressurized air to the upper surface of said plate means and to said side of said flexible diaphragm, and flexible means interconnecting said plate means and said vehicle.

Claim 15

A device as recited in claim 10 including in addition means for varying the dimension of said diaphragm for raising and lowering said plate means.

Claim 16

A device as recited in claim 11 in which said means for varying the dimension of said diaphragm includes a rotatable spool on said vehicle, said one longitudinal edge of said diaphragm being attached to said spool.

Claim 17

A device as recited in claim 10 in which said substantially rigid member includes a portion inclined upwardly and forwardly relative to said vehicle to an opposite edge thereof.

Claim 18

A device as recited in claim 10 in which said means interconnecting said plate means and said vehicle includes a diaphragm inclined upwardly and forwardly from the forward edge of said substantially rigid member to said lateral surface, and including in addition a conduit means providing communication between said lift chamber and the interior of said skirt arrangement, whereby pressurized air from said lift chamber inflates said skirt arrangement.

Claim 19

In combination with an air-cushion vehicle having a lift chamber having an open bottom, means for providing pressurized air in said lift chamber, and a generally rigid structure having a lateral surface spaced outwardly from the center of said lift chamber and extending along an edge of said lift chamber, a skirt arrangement for said lift chamber comprising a flexible diaphragm disposed longitudinally of said edge so as to present one side of said diaphragm adjacent said lift chamber, one longitudinal edge of said diaphragm being attached to said vehicle adjacent said edge of said lift chamber, a plate means, said plate means including an outer edge connected to the lower edge of said diaphragm, said plate means being inclined downwardly from said outer edge thereof to a portion thereof which is beneath said lateral surface, said plate means including an inner edge spaced outwardly from the center of said lift chamber and adjacent said lateral surface for permitting air to flow from said lift chamber generally horizontally outwardly under said plate means to the exterior of said lift chamber, said plate means including a first downwardly and inwardly inclined portion, and a second generally flat horizontal portion connected to the lower edge of said first portion at an obtuse angle relative thereto and extending inwardly therefrom to said inner edge of said plate, for being reacted upon by pressures above and below said second portion for moving said skirt arrangement upwardly and downwardly, aperture means in said generally horizontal portion of said plate means for discharging air from said skirt arrangement in a generally downward direction adjacent said second portion and constricting the outward generally horizontal flow of air from said lift chamber under said skirt arrangement, said aperture means including a duality of elongated slots, the first of said slots being adjacent the outer edge of said second portion and being inclined downwardly and inwardly for discharging a jet of air downwardly and inwardly therefrom, the second of said slots being inwardly of said first slot and being substantially vertically oriented for discharging a jet of air vertically downwardly therefrom, means for applying pressurized air to the upper surface of said plate means and to said side of said flexible diaphragm, and flexible means interconnecting said plate means and said vehicle.

Claim 20

In combination with an air-cushion vehicle having a lift chamber having an open bottom, means for providing pressurized air in said lift chamber, and a generally rigid structure having a lateral surface spaced outwardly from the center of said lift chamber and extending along an edge of said lift chamber, a skirt arrangement for said lift chamber comprising a flexible diaphragm disposed longitudinally of said edge so as to present one side of said diaphragm adjacent said lift chamber, one longitudinal edge of said diaphragm being attached to said vehicle adjacent said edge of said lift chamber, a plate means, said plate means including an outer edge connected to the lower edge of said diaphragm, said plate means being inclined downwardly from said outer edge thereof to a portion thereof which is beneath said lateral surface, said plate means including an inner edge spaced outwardly from the center of said lift chamber and adjacent said lateral surface for permitting air to flow from said lift chamber generally horizontally outwardly under said plate means to the exterior of said lift chamber, said plate means including a first downwardly and inwardly inclined portion, and a second generally flat horizontal portion connected to the lower edge of said first portion at an obtuse angle relative thereto and extending inwardly therefrom to said inner edge of said plate, for being reacted upon by pressures above and below said second portion for moving said skirt arrangement upwardly and downwardly, aperture means in said generally horizontal portion of said plate means for discharging air from said skirt arrangement in a generally downward direction adjacent said second portion and constricting the outward generally horizontal flow of air from said lift chamber under said skirt arrangement, said aperture means including a duality of elongated slots, the first of said slots being adjacent the outer edge of said second portion and being inclined downwardly and inwardly for discharging a jet of air downwardly and inwardly therefrom, the second of said slots being inwardly of said first slot and being substantially vertically oriented for discharging a jet of air vertically downwardly therefrom, means for applying pressurized air to the upper surface of said plate means and to said side of said flexible diaphragm, and flexible means interconnecting said plate means and said vehicle.

Claim 21

In combination with an air-cushion vehicle having a lift chamber having an open bottom, means for providing pressurized air in said lift chamber, and a generally rigid structure having a lateral surface spaced outwardly from the center of said lift chamber and extending along an edge of said lift chamber, a skirt arrangement for said lift chamber comprising a plurality of skirt units substantially in end-to-end alignment along said edge of said lift chamber, with the ends of adjacent skirt units being in juxtaposition, said skirt units being unconnected to each other so as to be independently movable, each of said skirt units including a flexible diaphragm disposed longitudinally of said edge so as to present one side of said diaphragm adjacent said lift chamber, one longitudinal edge of said diaphragm being attached to said vehicle adjacent said edge of said lift chamber, a plate means, said plate means including an outer edge connected to the lower edge of said diaphragm, said plate means being inclined downwardly from said outer edge thereof to a portion thereof which is beneath said lateral surface, said plate means including an inner edge spaced outwardly from the center of said lift chamber and adjacent said lateral surface for permitting air to flow from said lift chamber generally horizontally outwardly under said plate means to the exterior of said lift chamber, means for applying pressurized air to the upper surface of said plate means and to said side of said flexible diaphragm, flexible means interconnecting said plate means and said vehicle, and an additional flexible diaphragm at either end of said skirt unit positioned at the ends of said first-mentioned diaphragm and the ends of said plate means, said additional flexible diaphragms covering less than the entire space at the ends of said skirt unit for allowing air to flow from one of said skirt units to the other.

Claim 22

In combination with an air-cushion vehicle having a lift chamber having an open bottom, means for providing pressurized air in said lift chamber, and a generally rigid structure having a lateral surface spaced outwardly from the center of said lift chamber and extending along an edge of said lift chamber, a skirt arrangement for said lift chamber comprising a plurality of skirt units substantially in end-to-end alignment along said edge of said lift chamber, with the ends of adjacent skirt units being in juxtaposition, said skirt units being unconnected to each other so as to be independently movable, each of said skirt units including a flexible diaphragm disposed longitudinally of said edge so as to present one side of said diaphragm adjacent said lift chamber, one longitudinal edge of said diaphragm being attached to said vehicle adjacent said edge of said lift chamber, a plate means, said plate means including an outer edge connected to the lower edge of said diaphragm, said plate means being inclined downwardly from said outer edge thereof to a portion thereof which is beneath said lateral surface, said plate means including an inner edge spaced outwardly from the center of said lift chamber and adjacent said lateral surface for permitting air to flow from said lift chamber generally horizontally outwardly under said plate means to the exterior of said lift chamber, means for applying pressurized air to the upper surface of said plate means and to said side of said flexible diaphragm, flexible means interconnecting said plate means and said vehicle, and an additional flexible diaphragm at either end of said skirt unit positioned at the ends of said first-mentioned diaphragm and the ends of said plate means, said additional flexible diaphragms covering less than the entire space at the ends of said skirt unit for allowing air to flow from one of said skirt units to the other.

Claim 23

In combination with an air-cushion vehicle having a lift chamber, means for providing pressurized air in said lift chamber, and a generally rigid structure having a lateral surface extending along an edge of said lift chamber, a skirt arrangement for said lift chamber comprising: a flexible diaphragm disposed longitudinally of said edge so as to present one side of said diaphragm adjacent said lift chamber, one longitudinal edge of said diaphragm being attached to said vehicle adjacent said edge of said lift chamber, a plate means, said plate means including an edge connected to the lower edge of said diaphragm, a first portion extending downwardly and inwardly from said edge thereof with respect to said lift chamber, a second generally horizontal portion beneath said lateral surface connected to the lower edge of said first portion at an obtuse angle relative thereto and extending inwardly therefrom with respect to said lift chamber, and a third portion connected to the inner edge of said first portion and extending upwardly and inwardly therefrom with respect to said lift chamber, said plate means including a duality of elongated slots, the first of said slots extending longitudinally of said plate means substantially at the connection between said first and second portions thereof, the second of said slots extending longitudinally of said plate means substantially at the connection between said second and third portions thereof, said second portion of said plate means being connected to said third portion of said plate means so as to be pivotal relative to said third portion of said plate means substantially about an axis extending generally along the line of connection between said second and third portions, said first slot being defined on one side thereof by the outer edge of said second portion of said plate means, means for so pivoting said second portion relative to said third portion for increasing the size of said first slot, means for applying pressurized air to the upper surface of said plate means and to said side of said flexible diaphragm, and means interconnecting said plate means and said vehicle, said means interconnecting said plate means and said vehicle being a second diaphragm, said second diaphragm extending from said portion of said plate means to said generally rigid structure, said second diaphragm being connected to the inner edge of said third portion of said plate means.

Claim 24

In combination with an air-cushion vehicle having a lift chamber, means for providing pressurized air in said lift chamber, and a generally rigid structure having a lateral surface extending along an edge of said lift chamber, a skirt arrangement for said lift chamber comprising: a flexible diaphragm disposed longitudinally of said edge so as to present one side of said diaphragm adjacent said lift chamber, one longitudinal edge of said diaphragm being attached to said vehicle adjacent said edge of said lift chamber, a plate means, said plate means including an edge connected to the lower edge of said diaphragm, a first portion extending downwardly and inwardly from said edge thereof with respect to said lift chamber, a second generally horizontal portion beneath said lateral surface connected to the lower edge of said first portion at an obtuse angle relative thereto and extending inwardly therefrom with respect to said lift chamber, and a third portion connected to the inner edge of said first portion and extending upwardly and inwardly therefrom with respect to said lift chamber, said plate means including a duality of elongated slots, the first of said slots extending longitudinally of said plate means substantially at the connection between said first and second portions thereof, the second of said slots extending longitudinally of said plate means substantially at the connection between said second and third portions thereof, said second portion of said plate means being connected to said third portion of said plate means so as to be pivotal relative to said third portion of said plate means substantially about an axis extending generally along the line of connection between said second and third portions, said first slot being defined on one side thereof by the outer edge of said second portion of said plate means, means for so pivoting said second portion relative to said third portion for increasing the size of said first slot, means for applying pressurized air to the upper surface of said plate means and to said side of said flexible diaphragm, and means interconnecting said plate means and said vehicle, said means interconnecting said plate means and said vehicle being a second diaphragm, said second diaphragm extending from said portion of said plate means to said generally rigid structure, said second diaphragm being connected to the inner edge of said third portion of said plate means.

Claim 25

A device as recited in claim 17 in which for said connection of said second portion to said third portion there are relatively narrow deflectable strips of said plate means extending transversely across said second slot between said second and third portions of said plate means.

Claim 26

A device as recited in claim 18 in which said first slot is inclined downwardly and inwardly relative to said vehicle, and said second slot is substantially vertical.

Claim 27

In combination with an air-cushion vehicle having a lift chamber having an open bottom, means for providing pressurized air in said lift chamber, and a generally rigid structure having a lateral surface spaced outwardly from the center of said lift chamber and extending along an edge of said lift chamber, a skirt arrangement for said lift chamber comprising a flexible diaphragm disposed longitudinally of said edge so as to present one side of said diaphragm adjacent said lift chamber, one longitudinal edge of said diaphragm being attached to said vehicle adjacent said edge of said lift chamber, a plate means, said plate means including an outer edge connected to the lower edge of said diaphragm, said plate means being inclined downwardly from said outer edge thereof to a portion thereof which is beneath said lateral surface, said plate means including an inner edge spaced outwardly from the center of said lift chamber and adjacent said lateral surface for permitting air to flow from said lift chamber generally horizontally outwardly under said plate means to the exterior of said lift chamber, means for applying pressurized air to the upper surface of said plate means and to said side of said flexible diaphragm, flexible means interconnecting said plate means and said vehicle, said flexible means being a second diaphragm extending from said portion of said plate means to said generally rigid structure, said plate means including a first portion extending downwardly and inwardly with respect to said lift chamber, a second generally horizontal portion conNected to the lower edge of said first portion at an obtuse angle relative thereto and extending inwardly therefrom with respect to said lift chamber, and a third portion connected to the inner edge of said first portion and extending upwardly and inwardly therefrom with respect to said lift chamber to said inner edge of said plate means, said second diaphragm being connected to the inner edge of said third portion of said plate means, said plate means including a duality of elongated slots, the first of said slots extending longitudinally of said plate means substantially at the connection between said second and third portions thereof, said second portion of said plate means being connected to said first portion of said plate means so as to be pivotal relative to said first portion of said plate means substantially about an axis extending generally along the line of connection between said first and second portions, said second slot being defined on one side thereof by the inner edge of said second portion of said plate means, and means for so pivoting said second portion relative to said first portion for increasing the size of said second slot.

Claim 28

In combination with an air-cushion vehicle having a lift chamber having an open bottom, means for providing pressurized air in said lift chamber, and a generally rigid structure having a lateral surface spaced outwardly from the center of said lift chamber and extending along an edge of said lift chamber, a skirt arrangement for said lift chamber comprising a flexible diaphragm disposed longitudinally of said edge so as to present one side of said diaphragm adjacent said lift chamber, one longitudinal edge of said diaphragm being attached to said vehicle adjacent said edge of said lift chamber, a plate means, said plate means including an outer edge connected to the lower edge of said diaphragm, said plate means being inclined downwardly from said outer edge thereof to a portion thereof which is beneath said lateral surface, said plate means including an inner edge spaced outwardly from the center of said lift chamber and adjacent said lateral surface for permitting air to flow from said lift chamber generally horizontally outwardly under said plate means to the exterior of said lift chamber, means for applying pressurized air to the upper surface of said plate means and to said side of said flexible diaphragm, flexible means interconnecting said plate means and said vehicle, said flexible means being a second diaphragm extending from said portion of said plate means to said generally rigid structure, said plate means including a first portion extending downwardly and inwardly with respect to said lift chamber, a second generally horizontal portion conNected to the lower edge of said first portion at an obtuse angle relative thereto and extending inwardly therefrom with respect to said lift chamber, and a third portion connected to the inner edge of said first portion and extending upwardly and inwardly therefrom with respect to said lift chamber to said inner edge of said plate means, said second diaphragm being connected to the inner edge of said third portion of said plate means, said plate means including a duality of elongated slots, the first of said slots extending longitudinally of said plate means substantially at the connection between said second and third portions thereof, said second portion of said plate means being connected to said first portion of said plate means so as to be pivotal relative to said first portion of said plate means substantially about an axis extending generally along the line of connection between said first and second portions, said second slot being defined on one side thereof by the inner edge of said second portion of said plate means, and means for so pivoting said second portion relative to said first portion for increasing the size of said second slot.

Claim 29

A device as recited in claim 20 in which for said connection of said second portion to said first portion there are relatively narrow deflectable strips of said plate means extending transversely across said first slot between said first and second portions of said plate means.

Claim 30

A device as recited in claim 21 in which said second slot is inclined downwardly and inwardly relative to said vehicle, and said second slot is substantially vertical.